The present invention relates to a paper post-processing device that conducts folding processing such as z fold, outside three fold, inside three fold, double parallel fold, inside four fold, outside center fold and inside center fold for papers of paper ejected from image forming apparatuses such as an electrophotographic copying machine, a printer, a facsimile machine and a multifunctional machine having various functions of the aforesaid machines, and in particular, to space saving for a paper fold processing section that is composed of a pair of folding rollers and to reduction of driving loads for opening/closing of the paired folding rollers.
Further, the invention relates to the post-processing device that drills holes for filing with a punch at prescribed positions on the transported paper, an image forming system in which the post-processing devices are connected and to a method to punch holes on papers.
There are provided paper post-processing devices each conducting post-processing such as punching processing and fold processing on a paper on which an image is recorded by an image forming apparatus such as a copying machine, a printer, a facsimile machine and that conducts folding processing such as z fold, outside three fold, inside three fold, double parallel fold, inside four fold, outside center fold and inside center fold for papers of paper ejected from image forming apparatuses such as an electrophotographic copying machine, a printer, a facsimile machine and a multifunctional machine having various functions of the aforesaid machines, and in particular, to space saving for a paper fold processing section that is composed of a pair of folding rollers and to reduction of driving loads for opening/closing of the paired folding rollers.
The paper post-processing device disclosed in TOKKAIHEI No. 10-148983 is composed of a pair of upstream fold-transporting rollers in a paper transportation path, a pair of downstream fold-transporting rollers and a pair of folding rollers, and it double folds a paper.
In the paper post-processing device disclosed in TOKKAI No. 2001-72321, there have been conducted fold processing such as Z fold, inside three fold and center fold, on a single paper, in a paper bundle center fold processing section that conducts center fold processing for plural papers.
In the paper post-processing device disclosed in TOKKAI No. 2001-261220, Z fold processing for one paper is conducted in the first post-processing section, and center fold processing for plural papers and fold processing such as inside three fold and center fold for one paper are conducted in the second post-processing section arranged at the downstream side of a binding processing section.
(Patent Document 1)
TOKKAIHEI No. 10-148983 (Paragraph number 0011 and FIG. 2)
(Patent Document 2)
TOKKAIHEI No. 2001-72321
(Patent Document 3)
TOKKAIHEI No. 2001-261220
The conventional paper post-processing device that conducts fold processing has the following problems.
(1) In the paper processing device described in Patent Document 1, its structure is complicated because each of a pair of transporting rollers which form a loop on a paper and a pair of paper folding rollers is constructed. Further, since a pair of upstream transporting rollers and a pair of downstream transporting rollers are arranged to be away from each other, a space occupied by each of them is large, which makes space saving difficult.
Further, in the paper post-processing device described in Patent Document 1, a recording paper (paper) is folded, and it is folded in a convex form toward the roller side, then, it is necessary to open the folded paper again to transport it, thus, it has been impossible to fold while holding an end portion of the paper.
(2) In the paper post-processing device disclosed in each of Patent Document 2 and Patent Document 3, there is a problem that the device is complicated in structure and is large in size, because a paper is taken into an intermediate stacker temporarily and then is subjected to folding processing.
In the folding processing such as three fold, center fold and Z fold on a single paper, there is a fear that a paper transport failure occurs in a long paper transport path that is inclined and inflected, because a paper is transported to a paper bundle center fold processing section arranged at the downstream side of a binding processing section, and is subjected to fold processing.
A paper fold processing section of the paper post-processing device proposed in TOKUGAN No. 2001-253077 by the present applicant for solving the aforementioned problem is composed of an upstream folding roller, a folding roller that can be in pressure contact with the upstream folding roller, a downstream folding roller and a folding roller that can be in pressure contact with the downstream folding roller, and it functions as a pair of transporting rollers wherein upstream two rollers and downstream two rollers transport a paper to the downstream side when introducing the paper.
A leading edge of the paper is transported by two paired transporting rollers respectively in upstream side and downstream side to the prescribed position where folding processing can be conducted, and when the paired transporting rollers stop, the upstream folding roller that is held at a certain spatial distance (approx. 3 mm) for the downstream holding roller is brought into pressure contact with the downstream folding roller through a displacement means such as a solenoid, thus, a pair of folding rollers are formed, and papers can be folded.
However, the paper post-processing device stated above is of the construction wherein the upstream folding roller that is held by a swing lever plate is brought into pressure contact with the downstream folding roller through the displacement means including a solenoid, when folding papers. Therefore, a problem that the structure turns out to be complicated and grows greater is caused, and there is further caused a problem that a load for driving the folding roller to bring it into pressure contact and to release it is great.
Further, in recent years, there are provided post-processing devices each conducting punching processing automatically for papers, for filing papers on each of which an image is formed by an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine or a multifunctional machine having the functions of the aforesaid machines. Owing to this, it is possible for an operator to save time for binding outputted papers to set them on a business punch and for positioning them to punch as in the past, which has resulted in an office work that is extremely efficient.
In the post-processing device of this kind, if punching is performed under the condition that each paper is shifted or inclined, a position of the punched hole is also deviated, resulting in a problem that paper edges are not trued up to be unbecoming when they are filed.
Therefore, in the past, registration processing wherein papers are made to hit a member that is in the direction perpendicular to the direction of transportation has been conducted, or accuracy of parts of transportation member has been enhanced for coping with deviation and inclination of papers.
As an example for coping with the problems stated above, Patent Document (see Patent Document 4) discloses a paper admitting device wherein, when a trailing edge of a paper passes through the first transporting roller, a relative difference of transporting speed is given to the first transporting roller and the second transporting roller to curve the paper between both rollers and to make the trailing edge of the paper to touch the first transporting roller for determining a punched hole position.
(see Patent Document 4)
Japanese Patent No. 3301195 (page 2)
However, in Patent Document 4, positions of punched holes are not regulated in the lateral direction of papers although punched holes are positioned in the direction of transport of papers, thereby, punched holes are shifted in the lateral direction of papers and inclined.
The invention has been achieved in view of the problems mentioned above, and its another object is to provide a post-processing device wherein a structure is simple, papers are aligned so that positional deviations of the papers both in the transport direction and in the lateral direction may not be caused, and thereby, dispersion of punched hole positions is eliminated so that papers may not be unbecoming when they are filed, an image forming system to which the post-processing device is connected, and a paper punching method.